Arduino is an open-source computer hardware and software
company, project and user community that designs and
manufactures kits for building digital devices and interactive objects
that can sense and control the physical world. Arduino boards may
be purchased pre assembled, or as do-it-yourself kits; at the same
time, the hardware design information is available for those who
would like to assemble an Arduino from scratch
Size of Arduino UNO

The Arduino platform has become popular among people just
starting out with electronics, and for good reason. Arduino is an
advantage, him does not need a separate piece of hardware to
load new code onto the board – you can simply use a USB cable.
Additionally, the Arduino IDE uses a simplified version of C++, making
it easier to learn to program. Finally, Arduino provides a standard
form factor that begins to contain the functions of the microcontroller into a more accessible package.